Quantifying transnational climate impact exposure: New perspectives on the global distribution of climate risk

Indicators used in climate change adaptation planning are largely based on estimates of national or local climate vulnerability. However, classic vulnerability indices do not consider cross-border effects and global interconnections. We attempt to reconcile this need for a broader perspective by developing a global index of exposure to transnational climate impacts, which we define as impacts that are transferred via flows between countries. The index integrates traditional climate vulnerability indicators with spatially-explicit teleconnections between specific countries and constitutes a first approximation of the distribution of such exposure globally. Our results indicate that even though climate risks emerging from within a country's borders are highly correlated with economic development and geography, the distribution of exposure to transnational climate impacts provides a much more complex picture of global vulnerabilities, which neither geography, nor economic development alone can explain sufficiently. This highlights the need to take a cross-scale and multidimensional perspective of climate risk. In order to support more robust adaptation planning, risk assessments should consider both transboundary and far-reaching teleconnected interdependencies between countries.